Process for printing nylon



Patented Feb. 6, 1945 PROCESS FOR PRINTHIG NYLON Charles FranklinMiller, Wilmington, Del., as-

slgnor to E. I. du Pont de Nemours & Company, Wilmington, Del., acorporation of Delaware No Drawing. Application February 10, 1943,Serial No. 475,433

'1 Claim.- 01. 8-70)' This invention relates to an improved process forthe printing of nylon with vat dyes.

When nylon is printed by the conventional printing methods with vatdyes, usingthe normal amount of alkalies and reducing agent in theprinting paste, it has been found that the designs are not clean-cut inoutline, and on discharge printing there occurs a halo about the designon illumination prints that is objectionable. While this lack ofsharpness and the halo can be corrected by subsequent treatment of thegoods with mild oxidizing agents such as hydrogen peroxide or sodiummeta-nitrobenzene sulfonate, or with mild non-volatile organic acids,such treatment involves an extra step and therefore adds to the expenseand time involved in the printing operations. I

It is an object of this-invention to provide a process for printingnylonwith vat dyes which will give directly patterns of sharp outline andwhich will notexhibit the halo on illumination prints.

It has been known that one of the characteristics'of nylon is itsspecial aflinity for most vat dye colors, making it possible to dye thisfiber with vat colors by employing mild agents and mild alkalies. In theprinting of cotton or other fabrics with vat dyes the alkali metalcarbonates are usually employed in place of the caustic alkalies, but inorder' to give satisfactory reduction during the ageing ofthe print itwas necessary to employ sufilcient alkali to permit complete solution ofthe vatted dye in the fiber if uniform and strong prints were to beobtained,

I have found that the lack of sharpness in the ordinary direct printsand the halo which occurs in printing by discharge methods on nylon canbe overcome by printing the vat colors on nylon with printing pastescontaining, in addition to the usual thickeners and color, an alkalimetal sulfoxylate-formaldehyde and very small amounts of an alkali metalcarbonate. Where in the usual printing methods from to of alkali metalcarbonate is employed, based on reduction in the amount of alkali willpermit colors that ordinarilydo not print cotton to be used on nylon,although in many instances, particularly in'the anthraquinone series,compounds which are not recognized as vat dyes for cotton have beenfound to color nylon in desirable shades, for it is known that nylonexhibits a peculiar affinity for dyes that is not exhibited by any othersingle fiber.

It is of course to be understood that, due to the varying properties ofthe vat colors, the amount of alkali that should be employed Within thelimits above specified will vary. In general, the indo-phenols and thesulfurized indo-phenol vat dyes require the least amount of alkali metalcarbonate, while the higher amounts may be employed with dyes oftheanthraquinone vat dye series without detrimental results. andthioindigos in generalrequire intermediate amounts of alkali within thelimits above stated.

This invention is applicable to the printing of nylon with vat dyes ofall classes, such as the indigo and thioindigo colors, the anthraquinonevat colors, and indo-phenols and sulfur dyes.

In addition to givin prints having good sharpness of outline, or printsthat are free from halo, the use of the smallets'tdnounts of alkalimetal carbonates permits the preparation of printing pastes ofimprovedkstability because there is less chance for premature reductionof of the alkali metal sulfoxylate formaldehydes employed generally inthe printing of vat dyes. the examples below, the sodium sulfoxylateformaldehyde used is considered to be only sodium sulfoxylate'formaldehyde, but in practice the commercial grades will be found tocontain from 0.5% to 3.0% alkali as sodium carbonate, so that in manycases no alkaline agent other than that present as an impurity in thereducing a ent need be added to the printing paste. The thickeningagents employed are those normally used in the printing of vat dyestufison cotton and other cellulose material. g

The following examples are given to illustrate the invention; The partsused are by weight.

The indigos ample 1 Parts 20% paste of Indigo 16.0 Sodium sulfoxylateformaldehyde 10.0 Sodium carbonate 0.3 Thickening 74.7

The above described printing paste when printed on nylon, aged minutesin a vat color ager to reduce the color, oxidized and finished in theusual manner for vat colors of this series gives a print of deepblue'shade which is characterized by a sharpness of mark superior tothat obtained with printing compositions containing the normal amountsof potassium carbonate (5% to and is equal thereto in strength andbrilliance. Example 2 I Parts 18% paste of Sulianthrene Blue GR 20.0Sodium sulioxylate formaldehyde.- 5.0 Glycerin 2.5 Sodium carbonate 0.1Thickening 72.4.

The above described printing paste when printed on nylon, aged 5 minutesin a vat color ager to reduce the color, oxidized and finished in theusualmanner for vat colors of this type, gives a navy blue design of thesame superior sharpness of outline as described in Example 1.

Example 3 4 Parts 15% paste of Sulfanthrene Orange R"--- 20.0 Sodiumsultoxylate formaldehyde. 15.0 Sodium car 0.5 Diethylene glycol 2.0Thickening 62.5

' manner for vat colors, gives a bright orange design, tree of theha-lo" produced when the usual amount of (5% to 15%) potassium carbonateis used in the above formulation.

. As further illustrative of commercial printing colors of the vat dyeclasses, mentioned above, that may be substituted for the colors used inthe above examples, that have been found to give improved prints whenapplied according to this invention, are:

Trade name Colour index No.

Du Pont Indigo 20% Pasta-" 1177. Sulianthrene Orange R 1217.Sulianthrene Blue 213D Paste; 118 4. sullianutahrene Brilliant Blue 46Doubl 1189.

as Sulianthrene Bed 313 Paste. 1212. (Jiba Violet R Paste 1222.Sulfanthrene Pink FB Paste. 1211. Bulianthrene Brown G Pmte. Prototype#121. Iso-thio-indigo Iso-thio-indigo Sulianthrene Pink FF Pas Prototype#109. Ciba Pink BG Paste"..- A dichloro-dlmetbylthioindigo. Ciba Red R1229. Ponsol Yellow AR Double Paste 1132. Indanthrene Golden Yellow GKADouble Halogeneted dibenz- Paste. pyrenequinone. Ponsol Jade Green; i.Ponsol Golden Orange G Double Paste- 1096. Ponsol Pink B Double PimtePrototype #123. Ponsol Red BN Paste 1162. Aigol Yellow GW l-benzoylamino aue thraquinone. Algol Red 56 1,4-dibenzoyl amino anthraquinone.Suliogene Brilliant Blue BGL. 961. 'Suliogene Fast Green YCF 1006.Sulianthrene Blue GR 069. Ponsol Brilliant Violet 4RN Paste....Prototype #117. Ponsol Golden Orange RR'I Pute 1097.

It is of course understood that any appropriate dischargeable groundcolor may be employed,

and that with the exception of the reduction in amount of alkali metalcarbonate employed, the usual printing, ageing, oxidizing and finishingmethods are employed.

Iclaim:

In the process of printing nylon dyed with a dischargeabie ground color,with a vat dye in which the vat dye is applied with the usual printingpaste containing an alkali metal sulioxylate formaldehyde reducingagent, the step which comprises employing as the only added alkali inthe printing paste an alkali metal carbonate equal to from 0.1% to 0.5%of the weight of the printing paste.

' CHARLESFRANKLIN MILLER.

